A Bulwell road had to be closed after asbestos fell from a lorry.
The incident happened in Hucknall Lane at about 4pm yesterday.
The road was closed in both directions and a cordon was put in place for safety precautions.
It caused delays to bus services and heavy traffic in the area.
Inspector Sukesh Verma, from Nottinghamshire Police, said: "Around 4pm we received reports that asbestos had come off a lorry on Hucknall Lane.
"As cars have driven over the material, the substance may have been activated."
As a precaution officers boxed off the area and the road was closed.
Specialists from the Nottinghamshire Fire and Rescue Service attended.
People living nearby were advised to close their windows and doors.